Research On Flow Rate Measurement Of Oil-gas-water Three-phase Fliw Based On EMD And ICA

During development of the oilfields, it is very important to predict and measure theflow rate of oil-gas-water three-phase flow accurately. Aiming at the most of theflowmeters require that the measured fluid should be single-phase or two-phase,oil-gas-water three-phase was separated in this paper, applied empirical modedecomposition and independent component analysis algorithm based on cumulant. At thesame time, flow of the fluid was measured through calculating the transit time inaccordance with time delay estimation method.Firstly, considering that the adaptive system would generate larger volatility whenthe weight vector was close to the best value in LMS time delay estimation method, animproved algorithm was studied. In order to decrease the error, the error function e(n) wascontrolled by filter. And GCC-PHAT-ργ weighed method was introduced into theimproved algorithm to correct the time-delay result. This algorithm improves theestimation precision of time-delay.Secondly, aiming at single channel blind signal separation asks for using one originalsignal estimate multi-signal characteristics, a separated method for gas phase compositionand liquid phase composition of oil-gas-water three-phase flow was studied, based onEMD and ICA algorithm. This algorithm applied empirical mode decomposition andindependent component analysis based on cumulant to extract the gas-phase signal andliquid-phase signal of oil-gas-water three-phase flow. An experiment for the simulationsignal and the measured signal was performed. The experiment result prove that thismethod is effective and feasible.Finally, the realization process of flow rate measurement of oil-gas-water three-phaseflow based on EMD and ICA was given, and the test had finished on the field simulationwell experimental platform in Daqing Oilfield. Gas phase information and liquid phaseinformation were separated from oil-gas-water three-phase flow conductance signal whichsampled from six-electrode conductance probe, obtained oil-water signal and gas-watersignal. The improved LMS adaptive filtering time delay estimation method was applied for time delay estimation of gas phase signal and liquid phase signal, and then the flow ofgas phase signal and liquid phase signal was received.